High-voltage isolation type VSP speed regulation circuit, PCB and controller thereof

Abstract

The invention discloses a high-voltage isolation type VSP speed regulation circuit, a PCB and a controller thereof. The VSP speed regulation circuit comprises a two-way comparator, an energy storage capacitor, an MOS tube and a photoelectric coupler. According to the invention, a two-way comparator is used as a level flipping generation element, an external analog quantity voltage is compared with a comparator reference voltage, and a first-way comparator generates a triangular wave by charging and discharging an energy storage capacitor; the reference of the second comparator is compared with the triangular wave, so that square wave signals with different duty ratios are output and detected by a capture port of the MCU; the electric shock risk in the operation process can be avoided, so that the development difficulty is reduced, and the output frequency is flexibly controlled.

Description

Technical Field

[0001] The invention relates to a VSP speed regulating circuit, a PCB board and a controller thereof, and in particular to a high-voltage isolated VSP speed regulating circuit, a PCB board and a controller thereof. Background Art

[0002] In existing motor control technologies, many solutions use transformers to reduce high-voltage signals to the range of MCU operating voltage to achieve high-voltage isolation. However, this method has a narrow voltage range and low linearity due to the characteristics of the transformer, making it difficult to meet accuracy requirements while isolating high voltage.

[0003] At present, some circuit solutions for motor speed regulation usually control the switching frequency of MOS tubes through external analog voltage to achieve stepless speed regulation. This solution requires MCU to automatically identify the analog signal corresponding to the frequency required by the motor and convert it into a control signal to control the switching frequency of the MOS tube. However, the implementation of such circuits is complex and requires complex software algorithms, which have real-time and stability issues.

[0004] The existing technology has obvious deficiencies in high-voltage isolation and speed control signal generation, such as a narrow voltage range after isolation, low linearity, insufficient real-time and stability of the speed control signal, and lack of adjustability. These problems limit the performance and scope of use of the motor controller. Summary of the invention

[0005] Purpose of the invention: The purpose of the present invention is to provide a high-voltage isolated VSP speed regulation circuit, a PCB board and a controller thereof to improve the range, accuracy and stability of signal speed regulation under high-voltage isolation, and reduce the cost and debugging difficulty.

[0006] Technical solution: A high-voltage isolated VSP speed control circuit according to the present invention comprises:

[0007] Dual comparator, used to convert external input analog signal into square wave signal;

[0008] The energy storage capacitor is connected across the inverting input terminal and the output terminal of the first comparator, and is used for charging and discharging when the output voltage of the first comparator is reversed;

[0009] The MOS tube is used to be turned on when the second comparator outputs a high level to discharge the energy storage capacitor, and is turned off when the second comparator outputs a low level;

[0010] The photoelectric coupler is used to isolate the square wave signal output by the second comparator and transmit it to the input capture port of the main control unit.

[0011] Preferably, the positive input terminal of the first comparator of the dual comparator is used as a reference voltage of the VSP input voltage after voltage division. When the VSP input voltage is higher than the reference voltage, the output voltage of the first comparator is reversed, and the energy storage capacitor starts to charge; the output terminal of the first comparator is connected to the reverse input terminal of the second comparator. When the reverse input terminal level of the second comparator is pulled low, the output terminal of the second comparator is high level, the MOS tube is turned on, the energy storage capacitor is discharged, the output of the second comparator is low level, and the MOS tube is turned off, thereby cyclically outputting a square wave signal corresponding to the duty cycle.

[0012] A PCB board described in the present invention has a high-voltage isolated VSP speed regulation circuit as described in any one of claims 1 to 2 printed on the PCB board.

[0013] A controller according to the present invention adopts the VSP speed regulating circuit according to claim 1 to perform operation control, comprising:

[0014] An AC module is used to invert the AC power supply into a DC power supply and output it to the DC module. The AC module includes a fuse connected in series with the live wire, a thermistor connected in series with the neutral wire, an X capacitor and a common mode inductor connected in parallel between the live wire and the neutral wire, a rectifier bridge and a filter capacitor;

[0015] The DC module is used to adjust the DC power output by the AC module through the primary side feedback of the transformer through the flyback chip, and output a stable DC voltage to power the components in the control module;

[0016] The control module is used to reduce the voltage output by the DC module through LDO to power the MCU, adjust the output through dual-resistance current sampling and FOC algorithm, and coordinate the work of each module;

[0017] The VSP speed control module is used to convert the external analog voltage into a square wave signal through a dual-channel comparator, and output it to the input capture port of the control module after isolation through a photoelectric coupler.

[0018] Preferably, it further comprises a main control unit, which is used to receive the isolated square wave signal output by the VSP speed regulation circuit and control the speed regulation of the motor according to the duty cycle and frequency of the square wave signal.

[0019] Preferably, the live wire series fuse in the AC module is used to blow when the loop current is too large to protect the subsequent circuit; the neutral wire series thermistor is used to suppress the surge current at the moment of power-on, and its resistance value decreases after the current stabilizes.

[0020] Preferably, the flyback chip in the DC module uses a voltage regulator diode as a feedback element to stabilize the output voltage within a deviation range.

[0021] Preferably, the DC module further comprises a transformer, a primary winding of the transformer is connected to a power supply terminal of the first comparator, and a secondary winding of the transformer is connected to a power supply terminal of the second comparator.

[0022] Preferably, the three-phase back electromotive force of the control module is compared with the corresponding value of the zero point after being sampled by the ADC, and when the two values ​​match, the coil excitation sequence is shifted to the next step.

[0023] Preferably, the filter capacitor includes an aluminum electrolytic capacitor and a film capacitor.

[0024] Beneficial effects: Compared with the prior art, the present invention has the following significant advantages: 1. The overall circuit peripheral topology is streamlined, the actual measurement is stable and reliable, the development cost is low, and the debugging difficulty is relatively low. It not only realizes high-voltage isolation speed regulation in a small space PCB board, but also improves the speed regulation range and accuracy of the external power supply; 2. A dual-path comparator is used to convert the external input analog quantity into a square wave signal of a certain frequency, and then the external signal is isolated from the circuit of the main control unit through an optical coupler. It does not need to use an MCU to collect analog signals, and can use pure hardware circuits to realize the conversion between analog and digital quantities; 3. A primary-side feedback power supply chip is used, which has an integrated high-voltage MOS and uses the breakdown current of the voltage-stabilizing diode as feedback. Compared with the traditional flyback power supply topology, its cost is relatively low, and the number of components is small, which is conducive to the overall PCB board layout. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 It is a schematic diagram of the VSP speed regulation module of the present invention;

[0026] Figure 2 is a schematic diagram of a DC module of the present invention;

[0027] Figure 3 is a schematic diagram of a control module of the present invention;

[0028] Figure 4 is a schematic diagram of an AC module of the present invention;

[0029] Figure 5 It is a 3D schematic diagram of the PCB control board of the present invention. DETAILED DESCRIPTION

[0030] The technical solution of the present invention is further described below in conjunction with the accompanying drawings.

[0031] A high-voltage isolated VSP speed control circuit comprises a dual-channel comparator (operational amplifier), an energy storage capacitor, a MOS tube and a photoelectric coupler, wherein an input signal VSP first passes through resistors R502, R504 and a capacitor C500, and then the signal enters a first comparator (operational amplifier) ​​U502-B, and the signal is input from its inverting input terminal (NA-), and a resistor R505 forms a feedback loop, and U502-B generates a triangular wave signal, and outputs the triangular wave signal from OUTA, and the triangular wave signal output by U502-B is pulled up by R507 and input to the inverting input terminal (NB-) of a second comparator (operational amplifier) ​​U502-C, forming a dual-channel comparator (operational amplifier), the source (S) of the MOS tube U501 is grounded, and the drain (D) is connected to the signal path, and resistors such as R509 form a feedback loop of U502-C, and U502-C further processes the triangular wave signal, outputs square wave signals with different duty cycles, and finally the square wave signal is output from OUTB.

[0032] The square wave signal output by U502-C is connected to the anode (ANODE) ​​of the photocoupler U503 through resistor R511, and the collector (COLLECTOR) of U503 outputs the signal AD_SPEED. Due to the isolation effect of the photocoupler, the output signal AD_SPEED is electrically isolated from the previous circuit and can be safely transmitted to the subsequent circuit for processing; the entire circuit is powered by +15V and VDD_5V power supplies. The +15V power supply is used to power components such as U502-A, U502-B, and U502-C, and the VDD_5V is used to power components such as the photocoupler U503 to ensure that each component can work normally. At the same time, multiple grounds (SGND, AGND) in the circuit provide reference potentials for the signal.

[0033] A controller adopts a VSP speed regulation circuit for work control. The controller consists of four parts: an AC module, a DC module, a control module and a VSP speed regulation module.

[0034] The high-voltage DC power supply output by the AC module serves as the input energy of the DC module, providing the components in the DC module with the required electrical energy for operation. The DC module outputs a stable DC voltage through the secondary winding of the transformer to power the control module components. The signal processed by the VSP speed regulation module is transmitted to the control module, and the control module adjusts the output through the control algorithm.

[0035] The AC module inverts the 220V AC power supply into a 310V DC power supply. After the 220V AC power supply is input, it is connected to the fuse F101 connected in series with the live wire. The fuse F101 is used to fuse itself when the loop current is too large to cut off the circuit and protect the subsequent circuit from being damaged. Then it is divided into two paths, one of which is connected to the protection and current limiting circuit composed of thermistors RV100, R103, R110, R111 and thermistor R100; the other is connected to the high-frequency filter circuit composed of C100 and C103; the 220V power supply after preliminary processing is connected to the filter circuit composed of common-mode inductor L100 and capacitors CX100 and CX101 to reduce the influence of power supply noise and other interference; the filtered AC power supply is connected to the rectifier bridge D100 and converted into a 310V DC power supply. The rectified 310V DC power supply then passes through the filter circuit composed of CX102, CX103, and C102 to output a relatively pure high-voltage DC power supply to power the DC module.

[0036] The DC module uses the VIPER22ASTR-E flyback chip for transformer primary side feedback regulation. Its switching frequency is 60KHz, the built-in transistor withstand voltage can reach 730V, and the continuous working voltage range is 8V~38V. The Zener diode is used as a feedback element. When the auxiliary side voltage is higher than 15V, it breaks down, and current flows through the FB pin of the flyback chip, reducing the built-in MOS switching frequency; when the auxiliary side voltage is lower than 15V, the Zener diode is not broken down, and no current flows through the FB pin, increasing the built-in MOS switching frequency, thereby stabilizing the output voltage within the 15V deviation range.

[0037] Among them, the drain (DRAIN) of the field effect transistor U101 is connected to one end of the primary winding PRI of the transformer Z104, the other end of the primary winding is connected to the power supply, the source (SOURCE) of U101 is grounded, the anodes of D101 and D102 are connected to one end of the primary winding connected to the drain of U101, and the cathodes are connected to the other end of the power supply to form a freewheeling loop; C105 and C109 are connected between the power supply and the ground to play a filtering role; R101 and C106 are connected in series and then connected in parallel at both ends of the primary winding to absorb the peak voltage; one end of the auxiliary winding AUX is grounded, and the other end is connected to the control circuit to provide power or feedback signal for the control circuit; one end of the secondary winding S-2 of the transformer Z104 is connected to the anode of the diode D104, the cathode of D104 is connected to the load or the subsequent circuit, and C115 and R104 are connected in series and then connected between the cathode of D104 and the ground to play a filtering and current limiting role.

[0038] The control module uses LDO to reduce the auxiliary side 15V to the 5V voltage required by the MCU. If the power supply voltage is normal, the red LED will be always on. The control method uses dual-resistance current sampling and cooperates with the FOC algorithm to input the appropriate current value to the control module. The three-way back electromotive force is sampled by the ADC and compared with the corresponding value of the zero point. When the two values ​​match, the coil excitation sequence will be changed to the next step.

[0039] Among them, the VDD_5V power supply is connected to the power pin of the MCU after passing through the circuit composed of resistor R500 and capacitor C500. At the same time, VDD_5V is further decoupled by TP509, C509 and C510 and connected to the MCU power-related pins to power the MCU. AGND is the ground pin to provide a reference potential for the circuit; KEY1-KEY6 are respectively connected to different GPIO pins of the MCU. When the key is pressed, the corresponding pin level state changes. The MCU identifies the key operation by detecting the pin level change; such as HIN_W, LIN_W, BEMF_W and other signals are connected to the corresponding pins of the MCU. The MCU collects three-way back electromotive force, phase current and other information through these pins for the motor control algorithm; MCU-DEBUG_SPDA and MCU-DEBUG_SPCLK and other pins are connected to the debugging interface; the MCU_RESET pin of the J501 connector is connected to the MCU reset-related pins for resetting the MCU; the J502 connector provides power and ground signals for easy connection with external devices.

[0040] The VSP speed control module is composed of a VSP speed control circuit, in which the dual comparator (operational amplifier) ​​power supply voltage is 15V, and the positive input end of the first comparator (operational amplifier) ​​U502-B is used as the reference of the VSP input voltage after being divided by 15V. When the VSP input voltage is higher than the reference voltage, the output voltage of the first comparator (operational amplifier) ​​U502-B is reversed, and the energy storage capacitor connected across the reverse input end and the output end of the first comparator (operational amplifier) ​​U502-B begins to charge; at the same time, the output of the first comparator (operational amplifier) ​​U502-B is connected to the reverse input end of the second comparator (operational amplifier) ​​U502-C. When the reverse input end level of the second comparator (operational amplifier) ​​U502-C is pulled low, the output end of the second comparator (operational amplifier) ​​U502-C is high level; at this time, the MOS tube U501 The voltage between GS is 15V, DS is connected to the ground, the reverse input terminal of the first comparator (operational amplifier) ​​U502-B is at a low level, the energy storage capacitor is discharged, the output of the second comparator (operational amplifier) ​​U502-C is at a low level, and the MOS tube U501 is turned off, thereby continuously outputting a square wave corresponding to the duty cycle, and connecting the output terminal of the second comparator (operational amplifier) ​​U502-C to the input terminal of the photocoupler U503, and the output terminal of the photocoupler U503 is connected to the MCU input capture port, thereby realizing isolated analog-to-digital conversion speed regulation.

[0041] A PCB board with an overall thickness of 1.6mm, a high voltage AC220V input ensuring an insulation spacing of more than 2.5mm; a high voltage DC310V ensuring an insulation spacing of more than 2mm; a spacing of at least 5mm between a VSP speed regulation module and a high voltage ground; a top and bottom copper thickness of 1OZ, a main circuit line width of 1.4mm, and a maximum operating power of 150W.

Claims

1. A high voltage isolated VSP speed control circuit, characterized in that: include: Dual comparator, used to convert external input analog signal into square wave signal; An energy storage capacitor is connected across the inverting input terminal and the output terminal of the first comparator, and is used for charging and discharging when the output voltage of the first comparator is reversed; The MOS tube is used to be turned on when the second comparator outputs a high level to discharge the energy storage capacitor, and is turned off when the second comparator outputs a low level; The photoelectric coupler is used to isolate the square wave signal output by the second comparator and transmit it to the input capture port of the main control unit.

2. The VSP speed control circuit according to claim 1, characterized in that: The positive input end of the first comparator of the dual comparator is used as a reference voltage of the VSP input voltage after voltage division. When the VSP input voltage is higher than the reference voltage, the output voltage of the first comparator is reversed, and the energy storage capacitor starts to charge; the output end of the first comparator is connected to the reverse input end of the second comparator. When the reverse input end level of the second comparator is pulled low, the output end of the second comparator is high level, the MOS tube is turned on, the energy storage capacitor is discharged, the output of the second comparator is low level, and the MOS tube is turned off, thereby cyclically outputting a square wave signal corresponding to the duty cycle.

3. A PCB board, characterized in that: The PCB board is printed with the high-voltage isolated VSP speed regulation circuit as described in any one of claims 1 to 2.

4. A controller, using the VSP speed control circuit of claim 1 for operation control, characterized in that: include: An AC module is used to invert the AC power supply into a DC power supply and output it to the DC module. The AC module includes a fuse connected in series with the live wire, a thermistor connected in series with the neutral wire, an X capacitor and a common mode inductor connected in parallel between the live wire and the neutral wire, a rectifier bridge and a filter capacitor; The DC module is used to adjust the DC power output by the AC module through the primary side feedback of the transformer through the flyback chip, and output a stable DC voltage to power the components in the control module; The control module is used to reduce the voltage output by the DC module through LDO to power the MCU, adjust the output through dual-resistance current sampling and FOC algorithm, and coordinate the work of each module; The VSP speed control module is used to convert the external analog voltage into a square wave signal through a dual-channel comparator, and output it to the input capture port of the control module after isolation through a photoelectric coupler.

5. The controller according to claim 4, characterized in that: The invention also comprises a main control unit, which is used for receiving the isolated square wave signal output by the VSP speed regulation circuit and controlling the speed regulation of the motor according to the duty cycle and frequency of the square wave signal.

6. The controller according to claim 4, characterized in that: The live wire series fuse in the AC module is used to blow when the loop current is too large to protect the subsequent circuit; the neutral wire series thermistor is used to suppress the surge current at the moment of power-on, and its resistance value decreases after the current stabilizes.

7. The controller according to claim 4, characterized in that: The flyback chip in the DC module uses a voltage regulator diode as a feedback element to stabilize the output voltage within a deviation range.

8. The controller according to claim 4, characterized in that: The DC module further includes a transformer, a primary winding of the transformer is connected to a power supply terminal of the first comparator, and a secondary winding of the transformer is connected to a power supply terminal of the second comparator.

9. The controller according to claim 4, characterized in that: The three-phase back electromotive force of the control module is sampled by the ADC and compared with the corresponding value of the zero point. When the two values ​​match, the coil excitation sequence is changed to the next step.

10. The controller according to claim 4, characterized in that: The filter capacitor includes an aluminum electrolytic capacitor and a film capacitor.

Images